Frequency control and synchronization of gunn oscillations

Claim 2

In combination with a semiconductor crystal of given dimensions made preferably of a III-V compound of the type which produces cuRrent oscillations having a predetermined natural oscillation frequency by the Gunn effect when a sufficient voltage is applied between two opposed surfaces thereof to produce an electric field extending between said surfaces and having a field strength which exceeds a critical value, oscillation control means including first voltage supply means connected between said crystal surfaces for producing, in said crystal, an electric field having a value not substantially greater than the critical field strength value, and second voltage supply means connected between said crystal surfaces for applying a high control voltage across said crystal of sufficient amplitude to vary the field strength in said crystal between an amount which is less than said critical strength and an amount which exceeds said critical strength for controlling the frequency of the current oscillations produced in said crystal.

Claim 3

An arrangement as defined in claim 1 wherein said first voltage supply means are arranged for applying a d.c. voltage to said crystal.

Claim 4

An arrangement as defined in claim 2 wherein the frequency of said high frequency control voltage is within a frequency range extending between the natural oscillation frequency of said crystal and one-half said natural oscillation frequency.

Claim 5

An arrangement as defined in claim 2 wherein the frequency of said high frequency control voltage is less than half the natural oscillation frequency of said crystal.

Claim 6

An arrangement as defined in claim 1 wherein the frequency of the high frequency control voltage produced by said second voltage supply means is so related to the natural oscillation frequency of said crystal as to cause the resulting current oscillations produced by said crystal to have a frequency which is an integral submultiple of the frequency of said high frequency control voltage.

Claim 7

An arrangement as defined in claim 5 wherein said first voltage supply means are arranged to apply a d.c. voltage between said surfaces of said crystal, the voltage supplied across said crystal by said first voltage supply means having a value sufficient to create an electric field in said crystal having said critical field strength value, and the frequency of said high frequency control voltage being less than two times the natural oscillation frequency of said crystal and greater than one-half said natural oscillation frequency, whereby the frequency, of the resulting current oscillations produced in said crystal is equal to one-half the frequency of the high frequency control voltage provided by said second voltage supply means.

Claim 8

An arrangement as defined in claim 5 wherein said first voltage supply means are arranged to apply a d.c. voltage between said crystal surfaces, the voltage applied across said crystal by said first voltage supply means being sufficient to create an electrical field in said crystal having a field strength which is less than said critical value, the frequency of said high frequency control voltage being less than two times the natural oscillation frequency of said crystal and greater than the natural oscillation frequency thereof, and the high frequency control voltage provided by said second voltage supply means having an amplitude sufficient to cause the frequency of the resulting current oscillations produced in said crystal to be equal to one-half the frequency of said high frequency control voltage.

Claim 9

An arrangement as defined in claim 5 wherein said first voltage supply means are arranged to apply a d.c. voltage between said crystal surfaces, the voltage applied to said crystal by said first voltage supply means producing an electric field in said crystal having a field strength which is less than said critical value, the frequency of the high frequency control voltage provided by said second voltage supply means being less than two times the natural oscillation frequency of said crystal and greater than the natural oscillation frequency there-of, and the amplitudes of the voltages produced by said first voltage supply means and said second voltage supply means being sufficient to cause the frequency of the resulting current oscillations produced in said crystal to be less than the frequency of the voltage produced by said second voltage supply means and to be an integral multiple of one-third the frequency of said high frequency control voltage.

Claim 10

An arrangement as defined in claim 1 wherein said oscillation control means further comprises amplitude modulating means connected to amplitude modulate said high frequency control voltage.

Claim 11

An arrangement as defined in claim 9, wherein said means for amplitude modulating said high frequency control voltage act to cause the current output from said crystal to be angularly modulated in accordance with the amplitude modulation applied to said high frequency control voltage, said first voltage supply means being arranged to apply a d.c. voltage between said crystal surfaces, the amplitude of the voltage applied by said first voltage supply means being less than that required for causing the field strength across said crystal to exceed said critical value, the frequency of the voltage applied by said second voltage supply means having a value which is less than the natural oscillation frequency of said crystal and greater than one-half said natural oscillation frequency and the sum of the amplitude of the voltage provided by said first voltage supply means and the lowest peak amplitude of said amplitude modulated frequency control voltage being greater than the voltage required to produce an electric field across said crystal whose field strength exceeds said critical value.

Claim 12

An arrangement as defined in claim 1 wherein said first voltage supply means are arranged to apply a d.c. voltage between said crystal surfaces, and said oscillation control means further comprise a three arm circulator having one arm connected across said crystal, a second arm connected across the output of said second voltage supply means, and a third arm for connection to a load circuit.

Claim 13

An arrangement as defined in claim 1 wherein said second voltage supply means comprises a frequency variable resonant circuit connected between said crystal surfaces for producing a high frequency control voltage having a frequency equal to the resonant frequency of said circuit.

Claim 14

An arrangement as defined in claim 1, further comprising a resonator device to which said crystal is operatively coupled to cause at least a portion of the resonant current flowing through said resonator device pass through said crystal in a direction substantially parallel to the direction of movement of charge carriers through said crystal under the influence of a voltage applied between its said opposed surfaces.

Claim 15

An arrangement as defined in claim 13 wherein said resonator device includes at least one wall having a recess in which said crystal is disposed.

Claim 16

An arrangement as defined in claim 13 wherein said resonator device is constituted by a cavity resonator.

Claim 17

An arrangement as defined in claim 13 wherein said resonator device is constituted by a resonant strip line including two strip conductors between said crystal is disposed.

Claim 18

An arrangement as defined in claim 16 wherein said crystal is mounted to be movable along the length of said strip line for varying to resonant frequency of said line.

Claim 19

An arrangement as defined in claim 1 wherein said second voltage supply means are constituted by a lumped parameter resonant circuit into which said crystal is connected for receiving a high frequency control voltage constituted by the resonant frequency voltage of said circuit, and said first voltage supply means are connected to apply a d.c. voltage between said crystal surfaces.

Claim 20

An arrangement as defined in claim 18 wherein said lumped parameter circuit is constituted by reactances whose values are variable for varying the frequency of the high frequency control voltage which said circuit applies across said crystal.

Claim 21

A Gunn effect oscillator comprising, in combination: a. a preferably III-V-compound semiconductor crystal of given dimensions of the type which produces current oscillations when the strength of an electric field produced by a first voltage supply means and applied between two ohmic contacts on said crystal exceeds a critical value; and b. means for applying across said crystal a high frequency control voltage to create an electric field the direction of which is parallel to the direction of movement of charge carriers in said crystal, the amplitude of said control voltage being sufficient to cause the field strength across said crystal to vary from a point below said critical field strength to a point thereabove, whereby said high frequency control voltage controls the current oscillations produced by said crystal.

Claim 22

A Gunn effect oscillator comprising, in combination: a. a preferably III-V-compound semiconductor crystal of given dimensions of the type which produces current oscillations when the strength of an electric field produced by a first voltage supply means and applied between two ohmic contacts on said crystal exceeds a critical value; and b. means for applying across said crystal a high frequency control voltage to create an electric field the direction of which is parallel to the direction of movement of charge carriers in said crystal, the amplitude of said control voltage being sufficient to cause the field strength across said crystal to vary from a point below said critical field strength to a point thereabove, whereby said high frequency control voltage controls the current oscillations produced by said crystal.

Claim 23

In an oscillator circuit of the type which includes a body of single conductivity type semiconductor material, to which there is applied an electric field above a threshold field at which the body exhibits a negative resistance characteristic due to a change in the mobility of the conduction carriers in the body, to produce output high frequency oscillations in an output connected to the body, the improvement comprising: a. input means connected to said body for applying an input voltage across the body which causes the threshold field for the body to be exceeded and said high frequency oscillations to be produced; b. said input means including means connected to said body forming a driving circuit resonant at a frequency lower than the frequency of said high frequency output oscillations; c. said negative resistance exhibited by said body when said threshold is exceeded to produce said high frequency oscillations causing the voltage in said driving circuit to resonate at said lower frequency.

Claim 24

In an oscillator circuit of the type which includes a body of single conductivity type semiconductor material, to which there is applied an electric field above a threshold field at which the body exhibits a negative resistance characteristic due to a change in the mobility of the conduction carriers in the body, to produce output high frequency oscillations in an output connected to the body, the improvement comprising: a. input means connected to said body for applying an input voltage across the body which causes the threshold field for the body to be exceeded and said high frequency oscillations to be produced; b. said input means including means connected to said body forming a driving circuit resonant at a frequency lower than the frequency of said high frequency output oscillations; c. said negative resistance exhibited by said body when said threshold is exceeded to produce said high frequency oscillations causing the voltage in said driving circuit to resonate at said lower frequency.